The new wood adhesives are made from natural resources such as soy flour and lignin. They may replace the formaldehyde-based wood adhesives currently used to make some wood composite products such as plywood, oriented strand board, particle board, and laminated veneer lumber products - all major components of home construction and many other uses.
One of these patented adhesives is currently cost-competitive with a commonly used urea-formaldehyde resin, researchers say, but does not use formaldehyde or other toxic chemicals. Formaldehyde fumes are associated with some health problems, including eye and throat irritation. The chemical has been shown to be a human carcinogen, and in some circumstances it may be a concern in some residential building products.
The other key advantage of the new adhesives is their superior strength and water resistance.
"The plywood we make with this adhesive can be boiled for several hours and the adhesive holds as strong as ever," Li said. "Regular plywood bonded with urea-formaldehyde resins could never do that."
The first commercial application of the adhesive will be to make decorative hardwood plywood for high-quality interior uses. But the adhesive can also be used in making softwood plywood, particleboard, medium density fiberboard, oriented strand board, and the laminated veneer lumber that is finding increasing use to replace conventional joists and beams in construction.'"/>